The alias utility creates or redefines alias definitions or writes the values of existing alias definitions to standard output. An alias definition provides a string value that replaces a command name when it is encountered.

An alias definition affects the current shell execution environment and the execution environments of the subshells of the current shell. When used as specified by this document, the alias definition will not affect the parent process of the current shell nor any utility environment invoked by the shell.

The unalias utility removes the definition for each alias name specified. The aliases are removed from the current shell execution environment.

alias assigns def to the alias name. def is a list of words that may contain escaped history-substitution metasyntax. name is not allowed to be alias or unalias. If def is omitted, the alias name is displayed along with its current definition. If both name and def are omitted, all aliases are displayed.

Because of implementation restrictions, an alias definition must have been entered on a previous command line before it can be used.

unalias discards aliases that match (filename substitution) pattern. All aliases may be removed by `unalias *'.

alias with no arguments prints the list of aliases in the form name=value on standard output. An alias is defined for each name whose value is given. A trailing space in value causes the next word to be checked for alias substitution. The -t flag is used to set and list tracked aliases. The value of a tracked alias is the full pathname corresponding to the given name. The value becomes undefined when the value of PATH is reset but the aliases remained tracked. Without the -t flag, for each name in the argument list for which no value is given, the name and value of the alias is printed. The -x flag is used to set or print exported aliases. An exported alias is defined for scripts invoked by name. The exit status is non-zero if a name is given, but no value, and no alias has been defined for the name.

The aliases given by the list of names may be removed from the alias list with unalias.

The following option is supported by alias:

-t

Sets and lists tracked aliases.

alias-name

Write the alias definition to standard output.

alias-name

The name of an alias to be removed.

alias-name=string

Assign the value of string to the alias alias-name.

If no operands are given, all alias definitions will be written to standard output.

     "%s=%s\n" name, value

This example specifies that the output of the ls utility is columnated and more annotated:

example% alias ls="ls -CF"

This example creates a simple "redo" command to repeat previous entries in the command history file:

example% alias r='fc -s'

This example provides that the du utility summarize disk output in units of 1024 bytes:

example% alias du=du -k

This example sets up the nohup utility so that it can deal with an argument that is itself an alias name:

example% alias nohup="nohup "

>0

One of the alias-name operands specified did not have an alias definition, or an error occurred.

>0

One of the alias-name operands specified did not represent a valid alias definition, or an error occurred.